diff --git a/distrho/DistrhoUI.hpp b/distrho/DistrhoUI.hpp
index 62c4ab9e..07adfa47 100644
--- a/distrho/DistrhoUI.hpp
+++ b/distrho/DistrhoUI.hpp
@@ -259,7 +259,7 @@ protected:
 
       The default implementation does nothing.
     */
-    virtual void uiFocus(bool focus, CrossingMode mode);
+    virtual void uiFocus(bool focus, DGL_NAMESPACE::CrossingMode mode);
 
    /**
       Window reshape function, called when the window is resized.
diff --git a/distrho/src/DistrhoPluginJack.cpp b/distrho/src/DistrhoPluginJack.cpp
index 3b0e9751..2b3bf654 100644
--- a/distrho/src/DistrhoPluginJack.cpp
+++ b/distrho/src/DistrhoPluginJack.cpp
@@ -100,7 +100,7 @@ static void initSignalHandler()
 // -----------------------------------------------------------------------
 
 #if DISTRHO_PLUGIN_HAS_UI
-class PluginJack : public IdleCallback
+class PluginJack : public DGL_NAMESPACE::IdleCallback
 #else
 class PluginJack
 #endif
diff --git a/distrho/src/DistrhoUI.cpp b/distrho/src/DistrhoUI.cpp
index a3c84d63..11b0c42f 100644
--- a/distrho/src/DistrhoUI.cpp
+++ b/distrho/src/DistrhoUI.cpp
@@ -161,7 +161,7 @@ void UI::sampleRateChanged(double)
 /* ------------------------------------------------------------------------------------------------------------
  * UI Callbacks (optional) */
 
-void UI::uiFocus(bool, CrossingMode)
+void UI::uiFocus(bool, DGL_NAMESPACE::CrossingMode)
 {
 }
 
diff --git a/distrho/src/DistrhoUIDSSI.cpp b/distrho/src/DistrhoUIDSSI.cpp
index 13a2395e..31e61428 100644
--- a/distrho/src/DistrhoUIDSSI.cpp
+++ b/distrho/src/DistrhoUIDSSI.cpp
@@ -93,7 +93,7 @@ struct OscData {
 
 // -----------------------------------------------------------------------
 
-class UIDssi : public IdleCallback
+class UIDssi : public DGL_NAMESPACE::IdleCallback
 {
 public:
     UIDssi(const OscData& oscData, const char* const uiTitle, const double sampleRate)
diff --git a/distrho/src/DistrhoUIInternal.hpp b/distrho/src/DistrhoUIInternal.hpp
index c34299e6..b5f48ab0 100644
--- a/distrho/src/DistrhoUIInternal.hpp
+++ b/distrho/src/DistrhoUIInternal.hpp
@@ -195,7 +195,7 @@ public:
     // -------------------------------------------------------------------
 
 #if DISTRHO_PLUGIN_HAS_EXTERNAL_UI
-    void exec(IdleCallback* const cb)
+    void exec(DGL_NAMESPACE::IdleCallback* const cb)
     {
         DISTRHO_SAFE_ASSERT_RETURN(cb != nullptr,);
         DISTRHO_SAFE_ASSERT_RETURN(ui != nullptr,);
@@ -228,7 +228,7 @@ public:
     }
 #else
 # if DISTRHO_UI_IS_STANDALONE
-    void exec(IdleCallback* const cb)
+    void exec(DGL_NAMESPACE::IdleCallback* const cb)
     {
         DISTRHO_SAFE_ASSERT_RETURN(cb != nullptr,);
 
diff --git a/distrho/src/DistrhoUIPrivateData.hpp b/distrho/src/DistrhoUIPrivateData.hpp
index be09a603..937bf591 100644
--- a/distrho/src/DistrhoUIPrivateData.hpp
+++ b/distrho/src/DistrhoUIPrivateData.hpp
@@ -239,7 +239,7 @@ public:
           ui(uiPtr) {}
 
 protected:
-    void onFocus(const bool focus, const CrossingMode mode) override
+    void onFocus(const bool focus, const DGL_NAMESPACE::CrossingMode mode) override
     {
         DISTRHO_SAFE_ASSERT_RETURN(ui != nullptr,);